Thinkpad T22 sound - how to get it back ?

[Tim Day <timday@bottlenose.demon.co.uk>]

My Thinkpad T22's sound used to work fine in Etch, then I started
tracking Lenny and that was fine too, until the snd-cs46xx.ko module
went missing when the 2.6.24-1-686 kernel appeared (firmware
distribution issue; see bug #464197).
For a while after that the fix was to module-assistant install
alsa-source, but that now fails to build with the 2.6.25-2 kernel
(see bug #490710).  And even if the build issue was fixed, the only RC
bug I can see in this area is #483918 calling for the removal 
of the firmware from alsa-driver too.

What's the most pragmatic solution for mere mortals ?  (I get the
impression that it's not just as simple as FTP-ing something
into /lib/firmware yet).

Thanks
Tim